The use of drilling fluids for the drilling of oil and gas wells is well known. Said drilling fluid serves many purposes, including suppression of reservoir fluid pressure, lubrication of drill pipe and drill bits, and cooling of bottom hole assemblies and the like. Said bottom hole assemblies may contain individual components such as bits, stabilizers, measurement while drilling tools and the like. Frequently, such bottom hole assemblies contain electronic sections such as microprocessors that are used to collect and/or transmit data collected by sensors placed in the bottom hole assemblies.
Drilling fluids may contain many different types of components such as mud, clay, weighting materials, chemicals, drill cuttings, metal shavings, and the like. The size of these components can vary from microns to inches. Additionally, drilling rig personnel may inadvertently drop tools, gloves, rags and/or other unwanted materials into a well bore. Such unwanted and/or undesirable solid materials, hereinafter referred to as debris, can be very harmful to the safe and efficient operation of drilling rigs and/or related drilling operations. By way of illustration, but not limitation, such debris can cause failures in the electrical components of bottom hole assemblies. As a result, it is often desirable to filter drilling fluid to remove debris and contaminants from said drilling fluids.
Many methods of filtering well bore fluids exist. One conventional method involves installing at least one filter apparatus into at least one tubular member while a plurality of tubular members is being run into a well bore; at least one filter apparatus is installed in a pipe section at the earth's surface, and is subsequently conveyed to a downhole location as part of an elongate pipe string. Said conventional downhole filter members typically each comprise a substantially cylindrical screen apparatus having an external upwardly-facing fishing neck disposed at an upper end. However, these types of filtration devices have many disadvantages including, without limitation, limited flow through area at said upper ends.
In some instances, it has proven beneficial to filter said drilling fluids at or near the earth's surface (that is, near the upper opening of a wellbore), such as on a drilling rig. Frequently, a substantially cylindrical filter screen apparatus can be installed at a well's surface and typically remains within drill pipe or other tubular workstring above a rig floor. In such cases, said substantially cylindrical filter screen must be removed from said pipe string following connection or disconnection of pipe segments (joints or stands) above the rig floor. During this process, the filter screen apparatus must be conveyed to an elevated location within a drilling rig derrick and removed from said pipe, which creates a drop hazard to personnel and/or property situated there below.
Alternatively, a filter apparatus is typically installed within a flow manifold situated between the mud pumps of a drilling rig and the inlet of a wellbore. Said flow manifolds typically include a Y-shaped flow junction member that permits removal of said filter apparatus from said flow manifold for cleaning and/or debris removal. However, said conventional flow junctions are relatively large and expensive; further, it is typically very time consuming to stop pumping operations, open said conventional flow manifold, remove a filter apparatus, clean/replace said filter apparatus, and then close the flow manifold in order to resume fluid pumping operations.
Thus, there is a need for a method and apparatus for filtering of drilling mud and/or other fluids. There is also a need for a filtering apparatus that can be retrieved from a surface fluid flow manifold, quickly, safely and efficiently. These needs, as well as many others, are satisfied by the invention herein disclosed.